Fluid motor



June 13, 1933. W T. HAM|LTON ET AL 1,914,091

FLUID MOTOR Filed Sept. 26, 1930 All. n ISMZS 11 24 l INVENTORX mwa-JMATTORNEYS Patented June 13, 1933 UNITED ys'lATE-s WALTER T. HAMILTON ANDGRO'VER F. ILGEN, 0F SPRINGFIELD, OHIO, ASSIGANBS T0 THE AIRETOOLMANUFACTURING COMPANY, F SPRINGFIELD, OHIOLA CORPOBA- 'rIoN 0F omo FLUIDxo'ron Application led September 26, 1930. SeriaTNo. 4845625.

vto the rotor shaft, the Vpreferable fluid ybe ing compressed air.

The object is' to provide an improvedv f means for exhausting the motivefluid from the cylinders.

In the accompanying drawing: v Fig. 1 is al view partly in elevation andpartly in longitudinal section of a fluid motor constructed inaccordance with our improved design.

Figs. 2, 3, 4, 5, 6 and 7 are transverse sections on the lines 2 2, 3 3,4-'-4,` 5 5., 6 6 and 7 7, respectively, of `F ig.,1, the-v1ew`1n Fig. 5showing the parts in a different working position.

Referring to the drawing, 1 lrepresents a` cylindrical, hollow shellhaving a reduced'" diameter hollow hub portion 2 extendingconcentrically from one end to forni a support for the forward bearingfor vthe rotor shaft, there being a bearing bushing 3 inserted in thehub portion 2. .The opposite end 4 of the shell 1 isv open and isinteriorly threaded as at 5 for a short distance in the bore 6. Variousparts incident to the construction are placedin the bore 6 4and are otherein concentrically held in alignment vwith the forward bearing 3,these parts being a hardened steel wear plate 7 at the forward end ofthe bore l6, a cylinder 8, a flat, hubbed disk 9 intowhich a rearbearing bushing 10 is pressed, and a threaded hose connection 11 whichserves to bind the parts tightly in the shell l.,

The rotor body is indicated at 12 and consists of a cylindrical bodyportion having shaft extensions at each end,`one being a comparativelylong reduced-diameterfextenysion 13, and the other a shorter extension14, the longer extension 13 projecting ybe-l yond the bearing 'bushing 3and terminating in a threaded end 13 to which tools of various sorts areto be attached, while the shorter end 14 is journaled in the bearing Therotor 12 revolvesivithin, but. is not in actual contact with thecylinder 8. This cylinderv 8 is constructed along the usual lines, themajorj ortionof the exterior surface being cylin rical and-adapted toclosely ft the bore 6 of the shell 1, while the bore 15 of the cylinderis oblong in charac- `ter as seen best 1n Fig. 3. By 'reason of theyconcentric disposal of the parts described the axis of rotation of therotor coincides with the longitudinal center line of the cylinder 8, andthe oblong bore 15 of the cyllnder 1s therefore equally divided on eachside of the rotor 'to formchambers.

The rotor body -portion 12 is provided y with a pluralityof equallyspaced slots 16 in which blades of the lsame length as the body 12 areftted,land are adapted to slide freely in a lradial direction and onrapid 'rotation of the rotor these blades tend to follow the contour ofthe oblong bore 15 of Ithe cylinder. Referring to Fig. 5, in which therevolving parts are shown in a different `working positionas compared tothe other views, it will be seen that the opposite blades 17, 17 arey incontact with the bore 15 of the cylinder at diametrically oppositepoints, and that the rotor hasbeen suiciently rotated to show smallspaces 18, 18.

yWhen a fluid under pressure is admitted to these small spaces the rotoris rotated in the direction `of the arrow, the pressure being maintainedbehind the blades for a suitable length vof time, usually terminatingwhen the 'blades reach the point indicatedfby the character 19. Themomentum of the rotor then brings other blades20, 20 in positionto'receive an impulse, resulting 'in a very rapid `rotation of therotor. r

vInasvmuch as each vblade must move vinwardly and outwardly twice ineach revo-v lution" of 'the rotor, and as the rotor revolves at veryhigh speeds, anobjectionable vibra-- tion of the motor develops duringoperation. The vibration may be v'very materially reduced by theemployment of blades formed of materials such as aluminum, hard rubber,hard fiber, or bakelite. However, while blades of such light materialsas were just 4mentioned are as'certainly. affected by centrifugal forcesas av'e metallic blades `of lite the reater friction of the preferredbakelade is such that the outward movements may be comparativelysluggish with the result' that, unless provision is made to preventJ it,the-contour of the oblong bore 1 5 is not closely followed, resulting inan ineflicient operation due to leakage of fluid during the impulseperiod. Simple and I effective means are described later in the as thetime of admission may be obtained in` a variety of ways, the method Weprefer to follow being as herewith described, it

y being stated at this time that although the drawing appears to showopposing flows of fluid whereby inefficient operation would result, yetby reason of the high speed of the rotonand the lag in the movements ofthe lcompressed fluid, impulse and exhaust periods, occu'r at thedesired times, this being lespecially true as regards the aid given incausing the blades to follow the contour of the oblong cylinder bore.

Atthe rearward side of each blade, referring to the directionofrotation, through the body portion of the` rotor a series of passages 2lare provided, these being -in a line parallel to the axis of rotation ofthe rotor. Each of these passages leads into an individual conduit 22which is drilled in an eccentric, longitudinal location `through theshaft extensionl4 and also through the body portion 12 to a pointjust inadvance of the foremost opening 21,- F ig. 1.

The conduits- 22 are'equallyy spaced from each other and are parallel tothe longitudinal axis of the rotor, and are plugged at the end of theshaft extension 14. In the shaft extension 14 a series of radial portopenings 23 are drilled one for each conduit4 22. lIn the stationary hub9 of the disk 9 and through the stationary bearing bushing 10 a pair ofdiametrically opposed elongated orifices 24 are. drilled which areadapted to register with the port openings 23. Air or other fluid underpressure is admitted to the chamber 25 formed in the interior of thehose connection 11 and passes through a conically formed strainer intoeach of the port openings 24:, and then into the nearest radial portopening23 inthe shaft extensionl 14 agfd then ipto the passage openings22 to thel outlet ports 2l behind each blade. l

Inasmuch. as two ports 24 are employed and as these are diametricallyopposite, itfollows that in the present case where four blades vare usedin the rotor, the fluid may flow only to two diametrically opposedseries of outlet ports 21 and thus cause an impulse to occur behind twoopposite blades,

in this instance, the blades E17 The time of admission and the cut-offIof the fluid to ports and passages described is goverlfed by the sizeand location of the ports 24 and23. In Fig. 5 the position ,isl shown atthe time when the fluid is about to be admitted, while in Figs. 2 and 3,the position at cutoff is shown. A y

As the rotor continues in its rotation a preliminary exhaust port visopened, this event occurring immediately after the time of cut-off, andshortly thereafter a secondary exhaust port is uncovered;t the objectfor the plurality of exhaust ports being for the purpose of providingample .exhaust port area' whereby the speed and power is increased bythe elimination of possible back pressure. The preliminary exhaust isafforded by openings 26 cut in the periphery of the Wear plate 7 as seenin Fig. 4. This plate closes` the` forward end of the cylinder 8 exceptat the notches mentioned, and there are provided exhaust a ertures27 inthe forward wall 27 of the s ell 1.

The secondary exhaust occurs when a blade haspassed over a series ofopenings 28,l Figs. 1 and 3, in the cylinder 8, this series beinglocated at a preferred oint and in a path parallel to the axis of)rotation and on diametrically opposite sides. These openings 28communicate with a large space 28' between the cylinder 8 and the shelll obtained by removing a portion of the exterior surface ofthe cylinder8 as bestseen.

in Figs. 3 and 5 and open directly atthe forward end into the exhaustaperture 27' c inthe shell l. In Fig. 3 the blades 20 are approachingthe edges 26 where the start of the preliminary exhaust is made, whilein Fig. 5 the blades 20 have passed these edges and exhausting of thepressure behind these blades is taking place. It will be noticed inFigs. 3 or 5 that the area of the aperture 27 for the passage of exhaustfluid is approximately equally divided as regards the quantity of fluidthat ma escape through the preliminary or secon ary exhausts. In0rdinary conditions a satisfactory speed and power may be obtained bythe use of either of the methods vof exhausting arrangements,

but by the combined arrangement the speed has been increased perhapsthirty per cent, an idle speed approaching twelve thousand revolutionsper minute being attained.

At 30 and 30 are shown dowel pins, this or somey other suitablearrangement being necessary to provide that the proper alignment of thestationary parts be maintained while at 31 a small pin is employed toalign the bearing bushing 10 and the hub 9', since the supply vports 23pass through these parts,

the pin 31 projecting into a longitudinal slot cut in the exteriorsurface of the bushing 10.

Referring to Fig. l, it will be seen that the fluid at ressure in thesupply ports 2,4; may travel Iby leakage in both directions along theshaft extension 14, it being impossible to secure a fluid tight joint asthe bush- 5 ing 10 also serves as a rear main bearing. This leakageaccumulates and tends to exert a pressure on the end of the shaft14 andon that portion of the rotor body indicated at 12', manifesting itselfto the extent that o ordinarily the motor would not operate due to theexcessive end thrust (to the right) of the rotor. Operationheretofore'has been secured by supplying a ball thrust bearing at theforward end of the rotor, but we have 5 developed an arrangement wherebywe not only eliminate the expensive ball thrust bearing, but alsoeliminate the thrust itself, by means which will now be described.

In Fig. 1, in the bearing bushing 10, a o small radial groove 32 isemployed to relieve or vent the pressure occurring at the end of theshaft extension 14, this groove 32 communicating with a longitudinalassage 33 in the bushing, Figs. 2 and 5, w ich 5 in turn communicateswith an annular recess 34 in the forward side of the disk 9. Part of thepressure which would accumulate on the end 12 of the rotor also leaksinto the recess 34, and since this recess is in communication with theexhaust passageways 28 through the medium of the radial grooves 35 inthe forward side of the disk 9, the whole amount of the pressure whichwould tend to cause end thrust is vented to 5 atmosphere and end thrustis thereby obviated.

In motors of this type it has been the practice to admit fluid underpressure bcneath the blades for the purpose of preventing chattering ofthe blades both upon the outward and inward movement thereof. In priorconstructions the fluid has been admitted to each of the blade slotsdirectly from the passage which supplies the motive 5 fluid for thcworking stroke of that blade through a comparatively wide port, as aresult of which, when that supply passage passes the exhaust port, thefluid will be rapidly exhausted from beneath the blade 0 and thepressure thereon relieved, allowing the blade to chatter for a portionof its inward movement. To overcome this defect, we have providedanjarrangement whereby the'fluid can exhaust but slowly from the 5 bladeslot during the time the passage which ply the fluid to the blade slotat a point in advance of thev beginning fof its working stroke. To ythatend, .instead of supplying the fluid to any one. blade'slot from thepassage which furnishes motive fluid for that particular blade, we havearranged to supf 'ply this motive fluid from the' fluid passageimmediately in advance of the blade. For example, referring to Fig. 3,the inlet ports have just begun to supply lmotive fluid to the passages21 to drive the blades 17 which are just starting on their workingstroke and it will be noticed that reduced orifices 36 lead from theconduits 22, to the bottom of the slots.beneath the blades 20 which arejust about to begin to move into the slots. Pressure will begin tobuildup beneath the blades 20 until by the time they have reached theposition -of the blades17 in this figure, a maximum pressure will exist.As soon as the blades 17 have passed the exhaust ports however areduction in pressure is had in those supply passages which havesupplied the slots of the blades 20, but, due to the fact that the fluidbeneath the blades can escape but slowly through the reduced orifices byreason of leakage by the blades, a fluid cushion is maintained beneaththe blades 20y not only through their entire working stroke but alsoduring the entire inward movement in the slots.

A conicalstrainer 37 formed of perforated sheet metal is employed toprevent ingress of forei matter into the motor proper. This strainer maybe a one-piece rolled member or pressed and formed from the flat; ineither event, the larger end is forced into an annular recess 37 in therear of the disk 9, while the smaller end is forced over the hub 9 andcrimped into a recess 38 in the outer surface thereof.

Lubrication of the rotative parts is accomplished by feeding" a smallamount of lubricant into the motor from a container (not shown), thelubricantl being carried by the fluid medium. Heretofore, the forwardmain bearing has received but scanty lubricant due to its position andthe fact that the lubricant was carried in the fluid stream, resultingin rapid wear or shut-downs to lubricate this bearing. By simplearrangements we are enabled to afford ample lubrication for thisbearing, one of the means being a plurality of openings leading from theexterior of the extended hub 2, a single opening 39 on each side of thehub being shown in Fig. 7. These holes are located in the path of theescaping motive fluid which tends to expand immediately on leaving theapertures 26, and aportion of the fluid stream therefore flows forwardlyalong the hub 2, with the result that a minute ricant then finds its wayinto the oil rooves 41 in the interior of the bushing 3 t rough openings42 leading from the circumferential groove 40. i

Another method of lubricating the rear 4end of the forward main bearingis by the `radial grooves 44 which are provided in the rearward side ofthe wear plate 7, Figs. 4c and 7. These grooves are small half-roundgrooves leading from those portions of the wear plate which are exposedto the pressure of the fluid, as best seen in Fig. 3, so that duringeach impulse, a small portion of lubricant is deposited therein andforced by the pressure into an annular space 4:5 directly at the rear ofthe bushing 3. The rotation of the shaft coupled with the effects of thefluid pressure readily cause the oil to work its way into the bearingbushing 3.

Having thus described our invention, we claim:

1. In a fluid motor, a casing, a cylinder in said casing, a rotor insaid cylinder, an elongated exhaust port in an end of said casingleading directly from the interior of said cylinder in an axialdirection, an exhaust passage between said cylinder and casingcommunicating with said port, said exhaust passage extending throughoutthe major portion of the length of said cylinder, said cylinder havingat least one exhaust opening leading to"'"said"passage.

2. In a luid motor for a cutting tool, a cylinder, a rotor in saidcylinder, an exhaust port at the tool end of the cylinder leadingdirectly from the interior thereof in an axial direction, a longitudinalexhaust passage in the wall of the cylinder leading to said exl' haustport and said cylinder having at least one exhaust opening leading tosaid passage, said exhaust passage extending throughout the majorportion of the length of the cylinder.

1n testimony whereof, we have hereunto set our hands this 19th day ofSeptember,

WALTER T. HAMILTON. GROVER F. LGEN.

nemesi

